Dear Dr. Roach: Decades ago, I served in the Marines and was wounded in action in the Korean War. While recuperating in the naval hospital, I was told by several doctors that the more important reading of blood pressure (which they took frequently) was the bottom number. Now I am told by my doctors at the Veterans Affairs medical facility that it is the top number that is more critical. I am confused. Can you help? — M.B.

Answer: Both the top number and the bottom number are important, and either of them might be more critical in any given person. Looking at the entire population, it is thought that systolic blood pressure (the top number) is probably more associated with risk of heart attack and stroke. However, some people have normal systolic but high diastolic (the bottom number) pressures, and do need treatment.

Physicians can get clues about the underlying cause of high blood pressure from the readings. An older person with very high systolic and low diastolic pressure may have calcified, stiff blood vessels or a leaky valve connecting the heart with the aorta (the aortic valve). A person with a low systolic and high diastolic may have some heart failure or may have a blockage in the aortic valve. Knowing more about an individual can help the doctor choose the best kind of medication.

I know it was decades ago, but I still thank you for your service.

Dr. Roach writes: A recent column about the side effects of statin drugs generated a lot of mail, mostly about alternatives to statin drugs in people who could not tolerate them. I had mentioned in the column that a four-week period of time off of statins followed by a trial of a different statin resulted in 60 percent of people being able to tolerate a statin. One person wrote in that twice-a-week rosuvastatin (Crestor) was effective. However, some people cannot take them at all.